Support is requested for a scientific meeting organized by the American Association for Cancer Research, Inc. (AACR). The conference, entitled "Cellular Responses to Environmental DNA Damage," will be held at the Banff Springs Hotel in Banff, Alberta, Canada, on December 1-5, 1991. The Co-Chairpersons for this conference are Drs. Philip C. Hanawalt and Malcolm C. Paterson. Dr. Hanawalt is Principal Investigator. This confer- ence will bring to the attention of both laboratory and clinical scientists the most recent findings in the area of how living cells respond to environmentally inflicted DNA damage, and the application of these findings to our understanding and control of mutation, cancer, and aging. The invited speakers are well-known investigators in this field. They will make 30- to 60-minute presentations. Approximately 200-225 other conference registrants will have the opportunity to present their own novel work during poster sessions. The deleterious consequences of DNA damage in mammalian systems include mutation, cancer lethality, and some aspects of aging. Most physical and chemical carcinogens interact primarily with DNA and are consequently mutagenic. Comprehensive international meetings in the field of DNA repair have been held in North America every 3-5 years. In the past year the pace of activity and discovery has quickened with the isolation and cloning of a number of human DNA repair genes, with new information on the intragenomic heterogeneity in DNA damage processing and mutagenesis, and with new insights regarding the processing of environmental DNA damage in humans, both in vitro and in vivo. It is important to place these new discoveries in the context of current cancer research, since they affect the direction in which this field now develops. We plan to convene most of the individuals who have made major recent advances in this field, along with a large group of cancer researchers, genetic toxicologists, and others working on basic mechanisms of how living cells respond to environmentally inflicted DNA damage. Participants will be drawn from a variety of scientific areas and all levels of training. from graduate students to senior basic scientists or clinical investigators. It is therefore anticipated that the conference will result in a fruitful exchange of information that will enrich current research and suggest new conceptual insights into the genesis and propagation of the neoplastic state.